Texas Instruments TI-84 Plus CE

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Operation overview

“Getting Started”: The most detailed operation manual, but there is also a lack of explanation.

“TI-Basic Programming Guide”: Description of the TI-Basic language

“Reference Guide”: Function list and TI-Basic command list

As you can see, the only instructions for a calculator are “Quick Start” and “Getting Started”.

Hardware

The TI-84 Plus CE (launched in 2015) is a number of improvements to the original TI-84 Plus launched in 2004. The order of evolution is TI-84 Plus / TI-84 Plus Silver Edition → TI-84 Plus C Silver Edition → TI-84 Plus CE.

The hardware has evolved considerably for the improvement of the old one. The main changes from the first generation are shown below.

LCD screen: Black and white 96 x 64 pixels → 16-bit color 320 x 240 pixels

CPU: Z80 15MHz → eZ80 48MHz

RAM: 48KB * → 256KB

Flash memory: 1MB → 4MB

Power supply: AAA battery x4 and SR44SW button battery x1 → Rechargeable built-in lithium-ion battery (1200mAh)

The initial model of TI-84 Plus was 128KB, but it was later reduced to 48KB. In any case, the user’s usable area is 24KB, so the specifications are the same from the user’s point of view.

LCD screens, CPUs and power supplies have come a long way. On the other hand, RAM and flash memory haven’t increased for 11 years.

The CPU eZ80 is an extended version of the Z80 and has a 3-stage pipeline, so in theory it will triple the performance even with the same clock as the Z80. Since the clock is 3.2 times, the performance is 3.2 x 3 = 9.6 times when calculated simply. However, this is the story when RAM is also 9.6 times faster.

Operability

It seems that the basic operation method has not changed much from the original TI-84 Plus. The keyboard layout has not changed either.

There are as many as 12 buttons assigned to call menus (buttons surrounded by the red line in the photo below). Furthermore, although it is not a menu, there are three more buttons that call up the setting screen and special functions.

Variable constraints

Variables are where there are many constraints. The names and numbers that can be used are fixed depending on the type of variable (excluding list type variables).

For example, the names of real variables can only be A, B, C, …, Z, θ. The only graph functions are Y1, Y2, …, Y9, Y0. The only matrices are [A], [B], [C], …, [J].

It is not possible to freely decide the variable name in this way except for list type variables.

This is reminiscent of old programming calculators and pocket computers.

 Old file system

The file system is not layered like a PC.

If you operate MEMORY menu → Mem Management / Delete → All, all types of variables and data will be displayed as if they are arranged in the same hierarchy.

The MEMORY menu displays the data in RAM and the data in flash memory together. The data in the flash memory is marked with *. Otherwise, the data is in RAM.

The file system has the concept of archiving, and moving variables and data in RAM to flash memory is said to be archiving. The archived data will no longer be available on the calculator. Instead, it has more RAM. Originally, it seems to be a function to prevent data from being lost by RAM reset.

However, there is no concept of archiving as an exception for image data. This is because image data cannot be stored in RAM, only in flash memory.

For some reason, the image data for the graph background can only be used with a low resolution of 133 x 83 pixels. When you transfer the graph image to the calculator with PC software (TI-CONNECT), the resolution is automatically set.

On the other hand, it seems that the image data of the graph itself can be handled with 320 x 240 pixels, but it is a file with a .8ci extension and is not in a format that can be displayed on a PC.

The file system also has the concept of grouping. The attached booklet called “Quick Start” only describes a part of the operation method, but does not describe what the necessary function is for. The instructions “Getting Started” (for OS 5.2) do not mention grouping at all. I was shocked by this.

The grouped file Ann grouped data in the file to the result calculator of variables and data will be overwritten.

Since it is such an old and quirky file system, it is difficult to understand if you are accustomed to the layered file system of your PC.